I had one of these battery chargers, bought by my father to run my Tri-Ang train set ( I mean model railway ! ) in the early 1960s.

Unfortunately, in the mid 1990s I was planning to recharge a car battery. My girlfriend helpfully plugged it into the wall socket, which was switched on; the croc clips were loose, unprotected ( see picture ) and touching each other. So, end of charger, and an acrid smell greeted me when I arrived home.

We here in the U.S. had our version of Halfords, J.C. Whitney Company of Chicago. They started out in 1915 and are still in business today. Their catalogues were packed with everything you may need for almost any car, truck or motorcycle, from radios to superchargers, pistons to seat covers. I still have one of their catalogues from 1971 & will post a few photos from it: